Decade Factor: Simon Cowell announced the new series of X Factor (Picture: Getty Images for Sony Pictures)

Simon Cowell made a surprise appearance in London on Thursday to launch the tenth series of The X Factor – and was in a jovial mood as he introduced its panel of judges.

The series boss, 53, declared he thinks the show seems as fresh as it was ten years ago – although seemed to struggle to remember the names of everyone involved.

‘It’s just so easy after ten years to get lazy and make the same show again, but the enthusiasm, the changes, the judging panel is fantastic,’ the mogul said, heaping praise upon Gary Barlow, Sharon Osbourne, Nicole Scherzinger and Louis Walsh.

With the show returning this weekend, Cowell was quick to add he still enjoys working on it – despite not appearing on the panel as the US version of the show steals him away – and that new changes to the format have kept it from turning stale.

‘It feels fresh, fantastic, and I’m very proud to be part of this show,’ he gushed, before playfully adding: ‘Once again I feel like a very proud daddy,’ making a joking reference to his impending fatherhood.

Forgotten? Xtra Factor hostess Caroline Flack has been joined by Matt Richardson to co-host the latest series – but Simon Cowell forgot his name (Picture: Getty)